Turpentine isn't generally very harmful if ingested in small quantities. It was used in folk remedies and elixirs for hundreds of years. However, it is generally toxic if taken in larger quantities and that could pose a grave danger to the mother as well as the fetus. I suppose it could be used successfully for an abortion. The woman would have to effectively poison herself just enough to kill the fetus or do enough damage so that is miscarries but not do so much damage that she couldn't recover from it herself. Good luck with that self-experiment.

NIH lists turpentine poisoning as one type of street abortion along with poisoning by other agents like bleach.

"Methods of unsafe abortion include drinking toxic fluids such as turpentine, bleach, or drinkable concoctions mixed with livestock manure. Other methods involve inflicting direct injury to the vagina or elsewhere—for example, inserting herbal preparations into the vagina or cervix; placing a foreign body such as a twig, coat hanger, or chicken bone into the uterus; or placing inappropriate medication into the vagina or rectum."

Could it theoretically be effective? Sure. It shares many of the same alkaloids rue does, and rue is without doubt an effective (although not particularly safe) abortifacient.

Was/is it effective? I'm not really sure. Because it was a home/folklore remedy, and because abortions were either illegal or so socially stigmatized they may as well have been, many women did not seek medical care for an abortion. Some of the women who took it and "lost the baby" may never have been pregnant in the first place. Others may have taken it along with doing something else to end the pregnancy, and attributed the effectiveness to turpentine. Many pregnancies are spontaneously ended around 7-8 weeks, for reasons known only to whatever divinity there may or may not be, and women who drank turpentine may have coincidentally experienced a spontaneous miscarriage that would have happened without the turpentine.

I can find no scientific studies showing it to be tested, much less effective, as an abortifacient. That doesn't mean it doesn't work, that means I don't think it's been tested.

I hope it goes without saying that I don't think anyone should try it today. Whether or not it's effective, it's certainly dangerous. There are far safer methods of abortion available today.

But no, it's unlikely that the fetus absorbing the turpentine would cause an abortion in the timeframe that Dr. Rofelty describes. If all it did was kill the fetus directly, you'd probably have a dead fetus in you for a few weeks, or even months, before the body expelled it.

Most herbal/folk remedies that cause abortion do so because they contain alkaloids that make you so damn sick that it disrupts the hormonal balance needed to maintain an early pregnancy, shuts down the kidneys so they can't support a pregnancy, and/or directly stimulates the uterus to contract and expel the embryo. (I suspect this is what oral turpentine does, like rue.) Or they physically irritate the uterus or cervix and cause it to contract. (Which might happen from turpentine shoved up the vagina on a rag.) Or they cause an infection in the uterus, which causes the embryo to die and/or causes contractions. (Which might happen if you shoved turpentine up the vagina on a dirty rag.)

All in all, ugly ways to abort a pregnancy, and none of them particularly foolproof, and good reasons to keep modern abortion techniques legal and readily available.